Many integrated circuits (IC) use a clock signal for timing or synchronizing different parts of a circuit. This clock signal is typically provided by an oscillator circuit.
One common form of oscillator circuit is a ring oscillator. In a simple arrangement, a ring oscillator is formed from a feedback circuit which includes a delay line and an inverter. The frequency of a ring oscillator is determined by the delay of the delay line.
One problem of typical oscillator circuits is that the clock frequency may vary with process, voltage, and temperature (i.e., PVT) changes. Therefore, the oscillator may need to be adjusted periodically to maintain a specified frequency, by adjusting the delay of the delay line.